Paytm Interview Experience (For Experienced)

Round 1:
This round was basically for DS:
1.Give me brief introduction about you.
2.Given a tree find distance between two nodes and return -1 if any of node does not exist.
3.Given a sorted and rotated array find a given element using binary search approach.

Round 2:
1.Brief introduction about previous work.
2.Write code to rotate a matrix by 90 degree.
3.What are Implicit objects in jsp?
4.How to define a function in jsp?
5.What you worked in Hadoop?
6.Whole code for JDBC connectivity.

Round 3:
1.Brief introduction.
2.What are jsp implicit objects.
3.Is out implicit object and which object is its replacement in servlet.
4.What is out of memory error in tomcat server.
5.How garbage collector works.
6.How to define a immutable class.
7.Where we can use final.
8.How to make object of a class if its constructor is private.
9.What if parameter of a function is final.